1. Field of the Invention
The present invention relates to a mobile communication roadside device, a mobile communication moving body-mounted device and a mobile communication system for sending a predetermined signal to a predetermined area along a movement route and performing predetermined communication with a moving body that responds to the predetermined signal as in, for example, a toll charging process of a highway tollgate using non-contact IC cards or the like.
2. Description of Related Art
In recent years, for vehicular toll road toll charging systems, the settling of toll charges without stopping the vehicle through the use of a non-contact IC card has been considered.
For example, as a system which executes toll charging on a vehicle that is cruising along a toll road, when communicating with a vehicle-mounted device having a communication function and an IC card read-write function (hereinafter referred to as a vehicle-mounted device) and a communicator provided at a toll gate (hereinafter referred to as a roadside device), one proposed system (Japanese Patent Laid-Open Application Hei-4-315282) performs toll charging by setting a communication sequence with a plurality of vehicles. In this system, when performing communication with a particular vehicle, sending of inquiry numbers to other vehicles inside a communicable area is suspended so that there will be no jamming of the communication. However, in this system, even after once finishing the toll charging process, when the same vehicle has not left the communicable area because of traffic or the like, there have been cases when communication is performed again and repeated toll charging is executed.
As a system for preventing repeated toll charging, one proposed system (Japanese Patent Laid-Open Application Hei-6-131590) prohibits signal receipt for a predetermined period of time at the vehicular side after once performing communication.
However, in this system, because a predetermined properly-set signal receipt prohibition time is always used, in case of heavy traffic, there might be cases when a vehicle has not left a communicable area even after the predetermined signal receipt prohibition time has elapsed. For such cases, toll charging is performed again. Moreover, on the other hand, if a long predetermined signal receipt prohibition time is set in consideration of heavy traffic, the vehicle might pass through the next toll gate (including the same toll gate when returning back) within such predetermined signal receipt prohibition time when there is no traffic and so, there is a possibility that toll charging will not be performed at the next toll gate.